JPH0684435B2 - Method for producing clay mineral-nylon composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention is a clay mineral excellent in rigidity and impact resistance.
The present invention relates to a method for manufacturing a nylon composite.

(Prior Art) Nylon resin is a thermoplastic and is used in many fields because of its low cost and good moldability. However, nylon resin has a drawback that it is weak against heat, its maximum usable temperature is as low as about 70 ° C., and that its mechanical strength is lowered at a temperature below room temperature.

In order to improve such defects, a method of reinforcing by adding glass fiber or the like (polyamide resin handbook) or a method of reinforcing by adding fibrous double chain structure type clay such as sepiolite [SLAcosta, E. Morales, MCOjed
a, J. Mate. Sci. 21 (1986) 725], and the like.

However, the above and prior arts have the following problems.

In the method of (1), when an attempt is made to improve the mechanical strength to a sufficient level, an extremely large amount of glass fiber is required, deformation such as warpage occurs during molding, and the surface of the molded product is defective. There are problems such as becoming.
In the further method, since the fibrous double-chain structure type clay has poor compatibility with the nylon resin, it is difficult to uniformly disperse it in the nylon resin, and as a result, the mechanical strength is increased to a satisfactory level. There is a problem that you can not.

As an improved method of the method of the prior art, there is a method of adding a fibrous double chain structure type clay pretreated with an organic material to a nylon resin [((SLAcosta, E. Morales,
MCOjeda, J.Mate.Sci.21 (1986) 725))]. Although the compatibility of the fibrous double-chain structure type clay pretreated with the organic matter with the nylon resin is improved, the fibrous double-chain structure type clay itself is agglomerated and dispersed in the primary particles. Since it is difficult to disperse it uniformly in the nylon resin, the mechanical strength of the molded product becomes insufficient as a result.

Further, as a result of research to overcome the above-mentioned problems, the present inventors have invented and proposed a nylon composite obtained by ionically reacting the fibrous double-chain structure type clay mineral with a monomer (Japanese Patent Application No. Sho-200). 62-86477 (see JP-A-63-251461). In this invention, since it is necessary to use a relatively large amount of amino acid as the monomer of nylon,
There is room for improvement in this respect.

(Problems to be Solved by the Invention) As described above, there are various conventional techniques as methods for improving the mechanical strength of conventional nylon resins, but no one having the above-mentioned properties has been found to the satisfactory extent.

Therefore, an object of the present invention is to provide a method for producing a clay mineral-nylon composite having excellent rigidity and impact resistance without impairing the original properties of nylon resin.

[Structure of the Invention] (Means and Actions for Solving the Problem) The method for producing a clay mineral-nylon composite according to the present invention comprises: 50 parts by weight of water;
A step of obtaining 00 parts by weight of an aqueous suspension or slurry, wherein the ratio of the nylon monomer is 1 to 30 parts by weight with respect to 100 parts by weight of the nylon monomer, the fibrous double chain structure type clay mineral as a solid content. A step of dissolving the nylon monomer in the water suspension or slurry, removing water in the water suspension or slurry in which the nylon monomer is dissolved, and melting the nylon monomer; and the nylon monomer. It is characterized by comprising the step of polymerizing.

The “nylon monomer” used in the present invention has 9 carbon atoms.
Up to amino acids, or lactam.

The first step is a step of obtaining an aqueous suspension or slurry of the fibrous clay mineral by mixing fibrous double-chain structure type clay mineral (hereinafter abbreviated as “fibrous clay mineral”) with water. .

Examples of fibrous clay minerals used in this step include sepiolite and palygorskite. In the normal state, these fibrous clay minerals exist in a state in which a plurality of fibrous substances are intricately entangled with each other to form a lump.

In this fibrous clay mineral, one fibrous material constituting the fibrous clay mineral preferably has a diameter of 0.002 to 0.1 μm and a length of 0.01 to 10 μm. Diameter is less than 0.002μm and length is 0.0
If it is less than 1 μm, the reinforcing effect is not sufficiently exerted, which is not preferable. The diameter exceeds 0.1 μm and the length is 10 μm.
If it exceeds m, warpage or sink marks are generated in the molded product, the dimensional accuracy is lowered, and the surface becomes rough, which is not preferable.

The amount of water mixed with the fibrous clay mineral is
50 to 700 parts by weight of water per 100 parts by weight, preferably 100
~ 700 parts by weight. If the amount of water used is less than 50 parts by weight, the fibrous clay mineral cannot be separated / dispersed into individual fibrous substances, and the nylon monomer cannot be dissolved in the next step, which is not preferable. The upper limit of the amount of water blended is not particularly limited, but if it is too large, it will be difficult to evaporate and remove water in the subsequent step, so it is necessary to take this point into account when determining. Therefore, when the blending amount of water is too large, the suspension or slurry of the fibrous clay mineral can be dewatered under pressure by a filter press or the like to form a wet cake if necessary.

By the treatment of the first step, the lumpy fibrous clay mineral can be separated and dispersed into the individual fibrous clay minerals constituting it. In the treatment of the first step, it is not always necessary to completely separate and disperse all the fibrous clay minerals into individual fibrous clay minerals, and several fibrous clay minerals may be used within the range not impairing the object of the present invention. It may be in the form of aggregates.

The second step is a step of dissolving the nylon monomer in the aqueous suspension or slurry of the fibrous clay mineral obtained in the first step.

Nylon monomer is water-soluble, for example, 6
Amino acids having up to 9 carbon atoms such as -amino-n-caproic acid or lactams such as ε-caprolactam and valerolactam can be used.

When an amino acid is used as the nylon monomer, the terminal amino group becomes N ⁺ H ₃ − or N ⁺ H − when melted,
On the other hand, fibrous clay minerals are negatively charged due to the composition of protons and hydroxyl groups inside. For this reason, the amino acid can be firmly bound to the fibrous clay mineral by ionic bonding and has excellent compatibility, so it is relatively easy to uniformly disperse the amino acid. By this, uniform dispersion can be further facilitated. Further, when lactam is used as a monomer of nylon, the lactam does not have much N ⁺ H ₃ − and N ⁺ H − when melted, and the compatibility is poor. The process treatment is particularly effective.

The blending amount of the water suspension or slurry of the nylon monomer and the fibrous clay mineral is such that the water suspension or slurry of the fibrous clay mineral is solid (excluding the water content) with respect to 100 parts by weight of the nylon monomer. Amount of fibrous clay minerals only)
As 1 to 30 parts by weight. If the amount of the aqueous suspension or slurry of the fibrous clay mineral is less than 1 part by weight, its reinforcing effect is not exhibited, and if it exceeds 30 parts by weight, the contact between nylon monomers is reduced, and the molecular weight of nylon is reduced. Becomes smaller.

The preferred blending amount is 3 to 20 parts by weight as the solid content of the aqueous suspension or slurry of the fibrous clay mineral based on 100 parts by weight of the nylon monomer.

The above-mentioned first step and second step may be a one-step treatment step by mixing the fibrous clay mineral and a nylon monomer dissolved in a predetermined amount of water.

The third step is a step of removing water in the suspension or slurry in which the nylon monomer is dissolved and melting the nylon monomer. The treatment of this step is performed under heating. The heating temperature can be appropriately determined depending on the melting point of the nylon monomer used, but is usually 70
It is about 210 ℃.

This heat treatment is preferably carried out with stirring, and this heat stirring operation is preferably carried out in a nitrogen atmosphere.

By the treatment of the third step, water is evaporated and removed, and the molten nylon monomer is used as a medium instead of water, so that the fibrous clay mineral still remains
The books can be evenly dispersed. It is desirable to completely remove the water in the treatment of the third step, but it is not necessary to completely remove it from the viewpoint of production efficiency.
It is sufficient to remove at least up to 10% by weight.

The fourth step is a step of polymerizing the nylon monomer.

The polymerization reaction is performed under heating. The heating temperature is preferably 260 to 270 ° C.

The clay mineral-nylon composite of the present invention can be obtained by performing the above-mentioned first to fourth steps.

Further, in the method for producing a clay mineral-nylon composite of the present invention, the fibrous clay mineral aqueous suspension or slurry obtained in the first step is further coupled between the first step and the second step. A step of treating with the agent can be provided.

As the coupling agent, vinyltrimethoxysilane,
Silane coupling agents such as β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and γ-aminopropyltriethoxysilane; titanate coupling agents such as isopropyltriisostearoyl titanate and isopropyltris (dioctylpyrophosphate) titanate. An aluminum-based coupling agent such as acetoalkoxyaluminum diisopropylate can be exemplified, and among these, a silane coupling agent is preferable.

The treatment in this step is performed by stirring and mixing the aqueous suspension or slurry of the fibrous clay mineral and the coupling agent so that they are sufficiently in contact with each other. By the treatment with this coupling agent, the hydroxyl group of the fibrous clay mineral reacts with the coupling agent, and further, the crystallization water in the fibrous clay mineral and the coupling agent cause a substitution reaction.

The amount of coupling agent used is fibrous clay mineral (solid content)
It is 0.1 to 50 parts by weight with respect to 100 parts by weight. This usage is
If it is less than 0.1 part by weight, the impact resistance is lowered, and if it exceeds 50 parts by weight, the tensile strength, bending strength and bending elastic modulus are lowered. The preferred amount of the coupling agent used is 0.2 to 30 parts by weight based on 100 parts by weight of the fibrous clay mineral (solid content).

By treating with such a coupling agent, the compatibility of the fibrous clay mineral with the nylon monomer is significantly improved, and the coupling agent acts as a cross-linking agent between the fibrous clay mineral and the nylon monomer. As a result, a more uniform dispersion is possible. In addition, since the coupling agent is more flexible than nylon, rubber-like properties can be imparted to the resulting composite, and impact resistance can be significantly improved.

After the treatment with such a coupling agent, the above-mentioned second
The clay mineral-nylon composite of the present invention can be obtained by performing the treatments after the steps.

The clay mineral-nylon composite of the present invention is useful as a material for general household appliances, general industry, automobiles, building materials, clothes, and the like.

(Examples) Examples 1 to 5 Sepiolite (one diameter 0.05 to 0.2 μm, length 0.5 to 1 μm) from Turkey was used as the fibrous clay mineral, and ε-caprolactam was used as the monomer of nylon. The composite of the present invention was produced as follows. The amount of each component used is as shown in Table 1, and the indication is in parts by weight.

First, sepiolite was added to water and sufficiently stirred and mixed by a Henschel mixer to prepare an aqueous suspension. next,
Ε-Caprolactam was added to this aqueous suspension, and they were sufficiently mixed by stirring to dissolve them. Then, the water suspension in which ε-caprolactam is dissolved is transferred to a stainless steel reaction container,
This was installed in the oil bath. Next, nitrogen was flowed into the reaction vessel while stirring the water suspension, and the inside of the reaction vessel including the inside of the water suspension was made into a nitrogen atmosphere. Then, while maintaining this state, the oil bath was heated to 150 ° C. to evaporate and remove water, and ε-caprolactam was melted. Then, the mixture was heated to 260 ° C. to carry out a polymerization reaction to obtain a complex of the present invention.

The obtained composite was molded by an injection molding machine to prepare a test piece. This product was subjected to a tensile test based on ASTM D-638. The results are shown in Table 1.

Comparative Examples 1 to 7 Comparative compositions were produced according to Examples 1 to 5 using the components having the compositions shown in Table 1. The compositions of Comparative Examples 7 and 8 were prepared by adding the same fibrous clay mineral as that of the present invention to nylon 6
It was obtained by melt-kneading with a twin-screw extruder.

A test piece was prepared using each composition in the same manner as in Examples 1 to 5, and a tensile test was performed. The results are shown in Table 1.

Examples 6 to 8 First, an aqueous suspension of sepiolite was prepared in the same manner as in Examples 1 to 5. Next, aminopropyltriethoxysilane was added to this aqueous suspension as a coupling agent and mixed with a Henschel mixer. Then, it was left to stand for 2 to 3 hours for sufficient reaction. After the reaction, ε-caprolactam was added and dissolved. This aqueous suspension in which ε-caprolactam was dissolved was transferred to a reaction vessel and polymerized in the same manner as in Examples 1 to 5 to obtain the complex of the present invention. The amount of each component used is as shown in Table 2. The display is a weight part display.

The obtained composite was injection-molded in the same manner as in Examples 1 to 5 to prepare a test piece. A Charpy impact test (according to JIS standard) was performed on this test piece. The results are shown in Table 2.

Comparative Examples 9 to 14 Comparative compositions were produced according to Examples 6 to 8 by using each component having the composition shown in Table 2. The compositions of Comparative Examples 11 to 14 were obtained by melting and kneading the fibrous clay mineral which had been subjected to the coupling treatment in the same manner as in the present invention together with nylon 6 by a twin-screw extruder.

A test piece was prepared using each composition in the same manner as in Examples 6 to 8 and a Charpy impact test was performed. The results are shown in Table 2.

[Effect of the Invention] According to the manufacturing method of the present invention, a composite having excellent rigidity and impact resistance can be obtained.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takesumi Nishio 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. 1 Inside Toyota Central Research Institute

Claims (2)

[Claims] 1. A process for obtaining an aqueous suspension or slurry of 50 to 700 parts by weight of water with respect to 100 parts by weight of a fibrous double chain structure type clay mineral, wherein a monomer of nylon is added to 100 parts by weight of the monomer of nylon. A step of dissolving the fibrous double-chain structured clay mineral as a solid content in the water suspension or slurry in a proportion of 1 to 30 parts by weight, the water suspension in which the monomer of nylon is dissolved, or A method for producing a clay mineral-nylon composite, comprising the steps of removing water in the slurry and melting the nylon monomer, and polymerizing the nylon monomer. 2. A step of obtaining an aqueous suspension or slurry of 50 to 700 parts by weight of water with respect to 100 parts by weight of fibrous double chain structure type clay mineral, wherein the aqueous suspension or slurry is 100 parts by weight of the solid content. Parts by weight of 0.1 to 50 parts by weight of the coupling agent, and 100 parts by weight of the nylon monomer to 100 parts by weight of the nylon monomer. Dissolving in the coupling agent-treated water suspension or slurry in a proportion of ˜30 parts by weight, removing water in the coupling agent-treated water suspension or slurry and melting the nylon monomer And a step of polymerizing the above-mentioned nylon monomer, and a method for producing a clay mineral-nylon composite.